Finding information through Internet and the WWW in 2002 about pediatrics Paul Nieuwenhuysen • Vrije Universiteit Brussel • Informatie- en Bibliotheekwetenschap, Universitaire Instelling Antwerpen België Invited lecture.
Download ReportTranscript Finding information through Internet and the WWW in 2002 about pediatrics Paul Nieuwenhuysen • Vrije Universiteit Brussel • Informatie- en Bibliotheekwetenschap, Universitaire Instelling Antwerpen België Invited lecture.
Slide 1
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 2
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 3
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 4
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 5
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 6
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 7
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 8
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 9
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 10
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 11
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 12
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 13
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 14
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 15
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 16
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 17
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 18
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 19
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 20
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 21
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 22
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 23
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 24
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 25
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 26
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 27
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 28
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 29
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 30
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 31
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 32
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 33
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 34
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 35
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 36
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 37
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 38
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 39
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 40
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 41
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 42
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 43
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 44
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 45
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 46
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 47
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 48
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 49
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 50
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 51
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 52
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 53
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 54
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 55
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 56
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 57
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 58
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 59
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 60
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 61
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 62
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 63
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 64
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 65
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 66
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 67
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 68
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 69
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 70
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 71
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 72
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 73
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 74
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 75
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 76
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 77
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 78
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 79
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 80
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 81
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 82
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 83
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 84
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 85
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 86
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 87
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 88
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 89
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 90
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 91
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 92
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 93
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 94
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 95
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 96
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 97
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 98
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 99
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 100
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 101
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 102
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 103
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 104
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 105
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 106
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 107
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 108
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 109
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 110
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 111
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 112
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 113
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 114
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 115
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 116
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 117
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 118
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 119
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 120
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 121
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 122
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 123
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 124
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 125
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 126
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 127
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 128
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 129
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 130
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 131
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 132
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 133
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 134
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 135
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 136
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 137
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 138
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 139
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 140
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 141
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 142
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 143
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 144
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 145
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 146
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 147
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 148
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 149
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 150
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 151
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 152
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 153
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 154
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 155
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 156
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 157
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 158
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 159
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 160
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 161
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 162
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»PDF
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
Google
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Google
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
PDF
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 2
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 3
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 4
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 5
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 6
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 7
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 8
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 9
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 10
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 11
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 12
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 13
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 14
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 15
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 16
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 17
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 18
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 19
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 20
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 21
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 22
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 23
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 24
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 25
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 26
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 27
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 28
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 29
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 30
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 31
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 32
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 33
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 34
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 35
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 36
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 37
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 38
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 39
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 40
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 41
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 42
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 43
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 44
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 45
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 46
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 47
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 48
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 49
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 50
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 51
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 52
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 53
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 54
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 55
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 56
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 57
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 58
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 59
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 60
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 61
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 62
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 63
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 64
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 65
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 66
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 67
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 68
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 69
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 70
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 71
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 72
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 73
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 74
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 75
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 76
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 77
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 78
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 79
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 80
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 81
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 82
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 83
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 84
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 85
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 86
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 87
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 88
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 89
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 90
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 91
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 92
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 93
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 94
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 95
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 96
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 97
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 98
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 99
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 100
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 101
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 102
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 103
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 104
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 105
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 106
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 107
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 108
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 109
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 110
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 111
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 112
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 113
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 114
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 115
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 116
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 117
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 118
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 119
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 120
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 121
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 122
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 123
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 124
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 125
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 126
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 127
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 128
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 129
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 130
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 131
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 132
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 133
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 134
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 135
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 136
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 137
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 138
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 139
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 140
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 141
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 142
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 143
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 144
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 145
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 146
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 147
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 148
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 149
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 150
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 151
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 152
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 153
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 154
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 155
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 156
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 157
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 158
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 159
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 160
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 161
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162
Slide 162
1
Finding information through Internet
and the WWW in 2002 about pediatrics
Paul Nieuwenhuysen
• Vrije Universiteit Brussel
• Informatie- en Bibliotheekwetenschap,
Universitaire Instelling Antwerpen
België
Invited lecture for medical doctors (specialists pediatrics)
Onze Lievevrouwziekenhuis, Mechelen, March 2002
These slides are available from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
2
De slides en bibliografie
van cursussen rond informatie
• Slides met hyperlinks zijn beschikbaar online via WWW
bij het studiemateriaal bij de cursussen binnen:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/chapters/
• Een bibliografie bij elk hoofdstuk is beschikbaar online
via WWW:
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/courses/bibliography/
3
Online access information
sources and services
Introduction
4
Discovering online access
information sources
Equipment and tools required:
»A microcomputer
»Data communication facilities
»Tools to locate information sources
»Some knowledge and skills
»...
5
Growing importance of computer
network information resources
• Networked information resources are growing at a high
rate, not only in volume but also in importance.
There are many sources there which are vital to research
and many others which are useful generally.
• To keep abreast of their field, most academics and
researchers will find an increasing need to use the
network for fast and efficient communication and for
access to information. If they don’t, they are likely to be
left behind, because most of their colleagues in
institutions around the world will be doing just that.
6
Online access to information:
avoid network traffic jams
To access from Europe online information sources in the
US, work when lines are not saturated.
(better in the morning than in the afternoon)
7
Internet based information sources:
problems / difficulties (Part 1)
• Redundancy and overlap:
On the one hand, there is too much information on some
topics; in other words, the redundancy and overlap are high in
many cases.
Too few information sources:
On the other hand, there are too few information sources on
some topics.
8
Internet based information sources:
problems / difficulties (Part 2)
• No order is imposed on most sources.
Quality checks / quality controls are not performed.
Related to this: it is not required to register new information
offered.
Is the information that you find real, honest, authentic?
9
Internet based information sources:
problems / difficulties (Part 3)
• Change is the only constant:
Information sources are constantly changing, growing, but
sometimes disappearing.
10
Internet based information sources:
problems / difficulties (Part 4)
• Scattering:
There is no single simple but powerful system to find
relevant information through the Internet.
In other words:
integration / aggregation is still far from perfect.
11
Internet based information sources:
problems / difficulties (Part 5)
• Slow:
The Internet is in many places and for many applications not
yet fast enough.
12
Internet based information sources:
problems / difficulties (Part 6)
• In conclusion:
Surfing, using the
Internet, the WWW,
can be a time sink instead
of a productive activity.
13
Internet based information sources:
how many? how much information?
In 2001:
• More than 1 000 million unique URLs in the total
Internet
• More than 10 terabyte (= 10 000 gigabyte) of text data
14
Increasing number
of online public access databases
7000
6000
5000
4000
3000
2000
1000
0
1975
1980
1985
1990
1995
Source: Gale Directory of Databases, 1997.
2000
15
Online access information
sources and services
Types of online access information systems
16
Types of online access
information systems
We can categorize the various online accessible information
systems in various ways:
»primary or secondary
»based on information contents that is offered
»online access method required (= communication protocol)
»freely accessible versus accessible for a fee
»computer file format
(Of course these categorizations are normally not
independent but related.)
17
Primary versus secondary
computer sources / systems / services
• Primary sources /systems /services
directly useful
• Secondary sources /systems /services
»helping to access / use the primary services
»“travel agencies”, “navigation services”, ...
18
Types of online access information
systems by contents
• Documents (with or without hyperlinks)
• Catalogues of editors and bookshops
• Online public access library catalogues (OPACs)
• Community/Campus-Wide Information Systems (CWIS)
• Online access databases about journal articles
• Electronic newsletters and journals
• Computer file archives (documents, programs)
• Interest groups (for instance Usenet Newsgroups)
• ...
19
Types of online access information
systems by access method
• Remote login information systems and
bulletin board systems (BBS) (telnet in the Internet)
• Anonymous ftp servers, in the Internet
• Usenet News servers
(nntp in the Internet)
• Gopher servers, in the Internet
• Wide Area Information Servers (WAIS), in the Internet
• World Wide Web servers = http servers (WWW),
in the Internet
• ...
20
Types of online access information
systems: “free” versus “fee”
Public access information sources
free of charge
Fee-based online information services
(NOT free of charge)
21
Types of online access information
systems: “free” for members only
Public access information sources
free of charge
Fee-based online information services,
made accessible “free of charge”
by an institute to its members
Fee-based online information services
(NOT free of charge)
22
Types of online access information
sources by file format
For instance:
»TXT (ASCII)
»GIF
»DOC
»JPG
»HTM, HTML,
SHTML,…
»PNG
»MPG
»PCX
»ASF
»TIF, TIFF
»…
»AVI
23
WWW sites
classified by contents
• Commercial: about 80%
• Other 20%:
others
20%
»Science and education
»Personal
»others
Commercial
80%
in 1999
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
24
Commercial information provided
through the Internet
• Most of the information that is freely available on the
WWW is provided by commercially oriented
organisations.
• Thus that information is not objective or scientific in most
cases, but subjective or perhaps even misleading, and
certainly attracting more attention than more scientific
information.
(Of course many information sources are also provided by commercial
organisations that belong to the so-called information industry, but these are
bound to supply more objective information of high quality, as this is their way to
survive commercially.)
25
WWW sites
classified by language
• English: about 87%
• Other languages: 13%
in 1999
other
languages
13%
English
87%
26
Online access information
sources and services
Internet-based encyclopedias
27
Encyclopedias accessible through
Internet and WWW
• Dictionaries and encyclopedias are the first choice among
many types of information sources,
»when we do not need detailed information on a common
topic
»when we want to prepare a more detailed search on an
unfamiliar topic, by searching for the right spelling,
synonyms, context,…
• Some dictionaries and encyclopedias are available
through the WWW free of charge.
28
Example
Encyclopedias accessible through
Internet and WWW: examples
• Encarta Concise Free Encyclopedia
»http://encarta.msn.com/
• Encyclopædia Britannica
only a small part is available free of charge
+ links to selected WWW sites
»http://www.britannica.com/
• Encyclopædia Britannica Concise
»http://education.yahoo.com/reference/encyclopedia/
29
Example
Encyclopedias accessible through
Internet and WWW: examples
• The Canadian Encyclopedia
(in English and in French):
»http://thecanadianencyclopedia.com/
30
Example
Encyclopedias accessible through
Internet and WWW: overviews
• A list / overview of encyclopedia on the Internet:
http://www.internetoracle.com/encyclop.htm
• Other lists of encyclopedia on Internet
can be found as a part of more general directories of
Internet-based information sources.
31
Online access information
sources and services
Internet search functions
built in browser software
32
The Internet search functions built
into browsers
• Some Internet search functions are built into common
leading browsers like
»Microsoft Internet Explorer
»Netscape
• When connected to the Internet, you can use
»The functions behind the “Search button”
»Searching through the “Address” form
33
The Internet search button of
browsers: introduction
Common graphical browsers provide a search function and
a search button. Examples:
Netscape, Microsoft Internet Explorer
34
The Internet search button of
browsers: comments (Part 1)
• Such a search function offers in fact no searching,
but (only) a link to a WWW site, often in the USA,
which offers links or gateways to search tools on other
servers.
• It is faster in many cases to contact search tools directly.
35
The Internet search button of
browsers: comments (Part 2)
• The gateways may offer only a limited view on the
properties of the real search tool used.
• Such a search function can confuse users who may think
that the searching capability is built more or less into the
browser software, while searching relies on external
servers.
36
Searching with browsers using the
address form: introduction
• A search for particular Internet documents can be
performed by typing in keywords in the address form,
when you are connected to the Internet,
for instance with
»Microsoft Internet Explorer
»Netscape
• This is based on transmitting the keywords to some
Internet index through the Internet.
37
Searching with browsers using the
address form: comments
+ An advantage is the ease of use.
- A disadvantage is that it less clear what really happens,
than when you access a well chosen and well known
Internet directory or Internet index directly.
38
Online access information
sources and services
Internet directories and indexes
39
Internet: meta-information about
Internet information sources
• in printed manuals and guides:
- it is not always possible to get a copy fast
- it costs money to get a copy
- they are soon out of date
• offered on the WWW!:
+ directly available when we want to use the Internet
+ many systems are accessible free of charge
+ most systems are regularly updated
• (“intelligent agent” software on client PC)
40
Internet: subject-oriented metainformation offered via WWW
Information about information sources: in the form of
»subject guides = texts with references
»subject hypertext directories = subject guides
»key word indexes, generated automatically, for searching
»collections of links or forms to the above
»(multi-threaded search systems)
41
Internet global subject directories:
introduction
• They are virtual libraries with open shelves, for browsing.
• They are manually generated, man-made by many
people.
• They can be browsed following a tree structure or a more
complicated variation.
• The most famous of these systems belong to the most
popular and most visited sites on the WWW: e.g. Yahoo!
42
Internet global subject directories:
structure
The structure corresponds to a classification that is in most
cases specific for the particular overview.
In other words: the well-known and classical universal
classification systems are not used in most Internet
directories.
43
Internet global subject directories:
limitations
• They cover only a small number of selected WWW sites,
in comparison with the total number of sites that are
accessible.
• They are suitable mainly for broad searches that can be
difficult to formulate in words, but NOT for more specific
searches that require combinations of several concepts.
Example
Internet global subject directories:
Yahoo!
• A hypertext global subject directory can be found at
http://www.yahoo.com/
and at many other sites, including
http://www.yahoo.co.uk/
• Entries are NOT rated.
• Accessible free of charge.
44
Example
Internet global subject directories:
Yahoo! links in pediatrics
• Health > Medicine > Pediatrics:
• International Pediatric Chat - for professionals to share information and education
regarding children's health care.
• National Med/Peds Residents' Association - organization for residents, practioners and
medical students interested in combined internal medicine and pediatrics.
• Neonatology Network - information and communication platform for neonatologists
and pediatricians.
• Pediatria OnLine - qui si parla di bambini, fra pediatri e con le famiglie.
• Pediatric Critical Care
• Pediatric Database (PEDBASE) - containing descriptions of over 500 childhood
illnesses.
• Pediatric Endocrinology Conference - LWPES/ESPE joint meeting occuring July 6-10
2001.
• Pediatric Endoscopic Photos - illustrating intestinal problems in children.
45
Example
Internet global subject directories:
Yahoo! for pediatrics
• Health
> Medicine
> Pediatrics:
link to a digital library
(health sciences)
for young patients
46
Example
Internet global subject directories:
Yahoo! to pediatrics organisations
• Health
> Medicine
> Pediatrics
> Organizations:
link to the
American Academy
of Pediatrics
47
Example
Internet global subject directories:
Yahoo! links to pediatrics schools
• Health > Medicine > Pediatrics
>Schools, Departments, and Programs
• University of Rochester - partnership between pediatric residents and
community-based agencies that serve children and their families.
• Michigan State University@
• Royal College of Paediatrics and Child Health - responsible for training,
examinations, professional standards, and organisation of child health
services for the UK.
• Tohoku University
• University of Alabama at Biringham - programs and training opportunities
in pediatrics. Also contains faculy information and sub-speciatlty
descriptions.
• …
48
Example
Internet global subject directories:
Yahoo! Example: link to an e-journal
• Health
> Medicine
> Pediatrics
>Journals:
link to an
electronic journal
49
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
50
Example
Internet global subject directories:
Yahoo! Example: link to a directory
• Health
> Medicine
> Pediatrics
>Web
directories:
link to a
directory
of sites on the
WWW related
to pediatrics
51
Example
Internet global subject directories:
searching with a query in Yahoo! (1)
• The directory of Yahoo! can not only be browsed, but can
also be searched with a query.
• However, in this way the hierarchical structure is not well
exploited.
• For the formulation of a search query, Yahoo! can provide
automatic assistance related to spelling and word
variations.
For instance:
After searching for “Capetown”, Yahoo! Answers:
Other Spellings: Try searching for cape town instead.
52
Example
Internet global subject directories:
searching with a query in Yahoo! (2)
• When such a query does not provide results, then Yahoo!
uses a much larger external Internet index (not produced
by Yahoo!) to execute a query based on textual search
statements.
The chosen Internet index has varied over time.
• This mechanism is not made very clear and may confuse
the user.
53
Example
Internet global subject directories:
Britannica
• A hypertext global subject directory can be found at
http://britannica.com/
• Entries are rated.
• Accessible free of charge.
• Combined and integrated with a great encyclopedia.
54
Example
Internet global subject directories:
BUBL
• A hypertext global subject directory to more than 10 000
WWW sites for the higher education community can be
found at
http://bubl.ac.uk/link/
• Accessible free of charge.
55
Example
Internet global subject directories:
BUBL for pediatrics
56
Example
Internet global subject directories:
Google directory
• A hypertext global subject directory can be found at
http://directory.google.com/
• Accessible free of charge.
• Very similar to the Open Directory Project.
57
Example
Internet global subject directories:
Librarians' Index to the Internet
• A hypertext global subject directory can be found at
http://www.lii.org/
• Accessible free of charge.
58
Example
Internet global subject directories:
LookSmart
• A hypertext global subject directory can be found at
http://www.looksmart.com/
• Links are offered to LookSmart by the Internet index
AltaVista.
• A search in the LookSmart index
is also executed with the Internet index AltaVista.
• Accessible free of charge.
59
Example
Internet global subject directories:
Open Directory Project
• A hypertext global subject directory can be found at
http://www.dmoz.org/
• Accessible free of charge.
60
Example
Internet global subject directories:
Resource Discovery Network
• A collection of hypertext subject directories that focus on
academic information sources can be found at
http://www.rdn.ac.uk
• Accessible free of charge.
61
62
Internet global subject directories:
lists of directories
• Many Internet global subject directories exist, but the
ideal one is not available.
• Overviews / lists of Internet subject directories exist also.
• Examples (accessible free of charge):
»http://www.surfnet.nl/
»http://searchengineshowdown.com/dir/
63
Internet subject directories:
non-global, more specific systems
a directory limited to
sources in/of a country or region
the
complete
WWW
a global
subject
directory
can lead to
a directory restricted to
a specific subject domain
(“portal”)
Examples
Internet subject directories focusing
on a specific subject domain (Part 1)
• Computer science & engineering:
http://www.ub.lu.se/eel/
• Social sciences:
http://www.sosig.ac.uk/
• Marine science and oceanography:
http://oceanportal.org/
64
Examples
Internet subject directories focusing
on a specific subject domain (Part 2)
• Medicine and healthcare: general:
• http://www.achoo.com/
• http://www.medscape.com/
• http://www.omni.ac.uk
• Medicine and healthcare: General pediatrics:
• http://GeneralPediatrics.com
• http://www.medscape.com/pediatricshome
• http://www.pedinfo.com/
65
Examples
Internet subject directories focusing
on a specific subject domain (Part 3)
• Fishing:
http://www.onefish.org/
• Art, architecture and the media:
http://www.adam.ac.uk/ or http://adam.ac.uk/
66
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
67
Example
Internet subject directories focusing
on a specific subject domain: example
• A directory
of sites on the
WWW related to
pediatrics
68
Examples
Internet local subject directories:
examples in Belgium
• http://yellow.advalvas.be/weblist.html
• http://search.msn.be/exploring/exploring.asp
• The guide developed by the public libraries in Flanders:
http://www.bib.vlaanderen.be/webwijzer
69
70
Internet indexes:
automated search tools
• Several systems allow to search for and to locate many
items (addressable resources) in the Internet in a more
systematic, direct way than by only browsing/navigating.
• These systems do NOT search the contents of computers
through the real Internet in real time and completely
when a user makes a query.
Searching in that way would be much too slow due to
limitations in the technology.
71
Internet indexes:
scheme of the mechanism
User searching for Internet based information
Internet client hardware and software
user interface to a search engine
Internet index search engine
Internet information source
Internet crawler and indexing system
database of Internet files, including an index
72
Internet indexes:
description of the mechanism
Each of these search systems is based on:
• a database of links to pages / URLs that can be retrieved
by searching with queries through a big index that is built
machine-made on the basis of the contents, the texts, of
these pages
(to build this database and to keep it up to date, pages are
continuously collected from the Internet by a “robot”
computer software system)
• a search system with a user interface in a WWW form, to
allow the user to search through that database
73
Example
Internet indexes:
AltaVista
The primary search interface can be found in the US:
http://www.altavista.com/
http://www.av.com/
(These addresses all lead to the same information.)
Mirror site in UK:
http://www.altavista.co.uk/
74
Example
Internet indexes:
AltaVista: features
• Allows full text searching of the WWW
• Allows advanced Boolean searching
(in “Advanced” mode)
• Offers relevance ranking of search results
• Offers a link to an Internet subject directory (Looksmart)
• Offers links to systems to find
images, sounds,… (multimedia) in the Internet
75
Example
Internet indexes:
AltaVista simple versus advanced
• “Simple” is suited for instance for searches
»with only 1 concept
expressed as a series of synonyms, narrower terms,...
such as a search for a person, a company, an institute,...
»when ranking is important
• “Advanced” is suited for instance for searches
»with more than 1 concept
so that an AND combination is useful,
besides an OR combination
»when ranking is not important
76
Example
Internet indexes:
Fast = All the Web
• The search interface can be found at:
http://www.alltheweb.com/
• You can search the WWW and ftp servers.
• The database is one of the biggest.
77
Example
Internet indexes:
Google (Part 1)
• You can search for WWW pages at
http://www.google.com/
• Does NOT offer/allow
»full Boolean searches;
»stemming/truncation.
78
Example
Internet indexes:
Google (Part 2)
• For retrieval an algorithm is used that takes into account
the links between WWW pages.
A retrieved page is ranked higher when
»many sites/pages point to it
»“important” sites/pages point to it
• Searches include full text searching of files on the WWW;
not only html pages, but also files in the formats
Adobe PDF, Microsoft Word, Microsoft Excel,…
79
Example
Internet indexes:
Google additional features
• Besides a system to search for WWW pages,
Google offers also
»a subject directory
»searching for images on the WWW
»searching an archive of Usenet messages +
posting to Usenet groups
• Thus Google has become a great integrator / aggregator.
80
Example
Internet indexes:
Hotbot
• The search interface can be found at
http://www.hotbot.com/
• You can search the WWW
• Based on an Internet index created by Inktomi.
• Allows advanced, Boolean searching.
81
Example
Internet indexes:
Lycos
• The search interface can be found at
http://www.lycos.com/
• Has been based on various databases of WWW pages
over time.
In 2001-2002: based on the Fast database of WWW pages,
that forms also the basis for the search system Alltheweb.
82
Example
Internet indexes:
MSN Web Search
• The search interface can be found with the search
functions build into Microsoft Internet Explorer and at
http://search.msn.com/
• Offered free of charge by Microsoft.
• You can search for Web content.
• Since 1998.
• Is based on an Internet index created by another
company.
83
Internet indexes:
coverage / size of each index
The indexes grow and their “size ranking” is variable.
Biggest systems in 2002:
•
AltaVista
•
(Fast =) All the Web (serving also Lycos)
•
•
Systems based on the INKTOMI database of WWW
pages, such as Hotbot, MSN Web search,…
84
Internet indexes:
delay in indexing new pages
• The great, well known, international Internet indexes
have a delay of more than 1 month in indexing new pages.
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• So they are not suitable to search for rapidly changing
recent information (such as “news”)
(unless they index a small selection of important news
sites more frequently)
85
Internet indexes:
non-global, regional systems
the complete WWW
a global Internet index
an index limited to
sources in/of a country or region
86
Internet indexes
for citation searching: introduction
• Some Internet indexes / search engines allow you to
search for documents / pages / URLs that link to a
particular page, to some URL that you already know
(such as one of the web pages that you have developed or
that you have made available yourself).
• Linking to a URL is similar to citing an information
source.
• Such search systems can be used to analyse web citations.
• Web citations are sometimes named “sitations”.
87
Examples
Internet indexes for citation
searching: examples of systems
• AltaVista
but note that “Simple search” and “Advanced search” may
give different results
• Hotbot
88
Internet indexes
for citation searching: query syntax
For details about the required query syntax, query
formulation, see the online manual or help pages of the
search system that you want to use.
89
Internet indexes for citation
searching: applications
• Citation searching on the WWW or on an intranet can be
used
»to get an idea of the importance, the fame, the impact of a
particular web document, as measured by the number of
links/citations to that page
»to find out who has considered a particular page as
interesting enough to make a link to
»to find comments/criticisms on a particular web document
90
Multi-threaded
Internet search systems: relations
User
an Internet meta-search system
Internet search system 1
Internet search system
database 1
Internet search system 2
Internet search system
database 2
WWW pages
91
Multi-threaded Internet search
systems: server-based or client-based
• Online accessible on a server in the Internet.
• On the client, “meta-search software”.
92
Coverage of Internet directories and
Internet indexes
Internet information sources
A global Internet directory
A global Internet index
93
Global Internet search tools:
a comparison
Global Internet
directories
Global Internet
indexes
Multi-threaded
search systems
• Only a limited
selection of Internet
sources
• About 1/3 of the
• These get information
Internet is covered by
from directories
an index
and indexes
• Browsing
information sources
is easy
• Searching requires
some skills and
knowledge
• Searching requires
some skills and
knowledge
• Good for broad
searches
• Good for specific,
narrow searches
• Good when even 1
index does not yield
information
94
Internet indexes cover only a part of
the Internet: introduction
The “visible” part of Internet
The “hidden, invisible” part of Internet and the WWW,
(that is not searchable using a global index
like, AltaVista, Google...)
95
Internet indexes cover only a part of
the Internet: scheme
telnet
ftp
...
Internet
WWW
CGI, ASP,...
Static indexable texts in the WWW
( = on HTTP server computers)
covered partly by Internet indexes
Rapidly changing information,
such as news
Databases
and
file archives
accessible through
the Internet
Word
files
Information accessible only
when passwords are used
files
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
96
Example
Database accessible over the Internet:
a famous example: Medline/PubMed
• Medline is a database of descriptions of articles in the
area of medicine, published in more than 4 000 scientific
journals.
• This database is accessible through several different
retrieval systems on the Internet and the WWW.
• Medline/PubMed is one of the systems that provide access
to the database. Available from
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• These systems are provided free of charge by the USA
National Library of Medicine.
97
98
Internet indexes cover only a part of
the Internet: conclusion for users
When you want to retrieve information about a particular
subject from the Internet, use not only WWW indexes,
but use also other sources accessible through the Internet
»anonymous ftp file archives,
»e-mail based interest groups; Usenet newsgroups,
»databases
(book and journal bibliographies, library catalogues,
archives of group messages, directories, atlases,…)
»rapidly changing information, such as news
»information accessible only when passwords are used
99
Gateways to Internet databases
accessible free of charge
• Most Internet search engines search classical, static
WWW pages and not databases accessible through the
WWW.
• However, some systems offer a gateway to search
databases on the Internet.
Examples:
• http://invisibleweb.com/
• http://www.invisible-web.net/
(See also other more general directories/overviews/lists of
Internet information sources.)
Example
Gateways to Internet databases
accessible free of charge: invisibleweb
100
101
Finding images on the Internet:
introduction
• Several public access search systems are available free of
charge to search for
images / pictures (either artwork, either photos, or both)
on the Internet.
• When searching for images, the search results from such
a system offer not only links to the image files on the
Internet, but also directly small versions of the images
(so-called “thumbnails”).
102
Examples
Finding images on the Internet:
examples of search engines
• http://alltheweb.com !!!
• http://gallery.yahoo.com/ !
• http://images.google.com/ !!!!
or through http://www.google.com/
• http://multimedia.lycos.com/
• http://www.altavista.com/ !!
(also audio and video, choose not the normal text search,
but IMAGES in the user interface.)
• http://www.ditto.com/ !
Examples
Finding images on the Internet:
screen shot of a Google image search
103
104
Guide to searching the Internet
available through WWW
• Searching the Internet:
recommended sites and search techniques. [Online]
Available from:
http://www.albany.edu/library/internet/search.html
• The RDN virtual training suite. [Online]
Available from:
http://www.vts.rdn.ac.uk/
offers training for users with a specific academic or
professional interest.
105
Current awareness services focusing
on WWW pages: introduction
• Tracking changes in one or more public access pages on
the WWW or finding new pages, is possible
»by using one of the available, suitable, programs loaded on
your client workstation
»through “alert” services based on a server on the WWW
—that track updates for the user/subscriber
—and send alerts by email to the user/subscriber
• Few systems are free of charge.
Example
Current awareness services focusing
on WWW pages: Tracerlock
• http://www.tracerlock.com/
can use one of several external Internet indexes with a
simple search query given by you, to discover relevant
changed or new WWW pages for you in the future
106
107
Online access information
sources and services
Public access book databases
108
Public access book databases:
introduction
• Even in this age of Internet-based information sources, a
lot of information is still distributed in the form of printed
books.
• The contents of most books is (still) not available on the
Internet.
• Most Internet search tools do NOT allow you
to find out about the existence of books that may be
interesting for you.
• So, specific search tools to find books can be useful.
109
Public access book databases:
an overview
• (Databases by publishers.)
• Databases by book distributors / bookshops!
• Online public access library catalogues
• (Databases of computer-based versions of books.)
110
Public access book databases provided
by bookshops
• To find currently available books, the bibliographic
databases assembled by big bookshops are interesting.
• Several offer a good coverage and
are accessible free of charge.
Examples
Book databases accessible free of
charge: examples (Part 1)
• Amazon.com (US):
http://www.amazon.com/
http://www.amazon.co.uk/
note: amazon, NOT amazone
• Barnes and Noble (US):
http://www.bn.com/
• Blackwell’s on the Internet
(International, academic books):
http://www.blackwell.co.uk/
111
Examples
Book databases accessible free of
charge: examples (Part 2)
• VLB for books in German
http://www.buchhandel.de/
• For books in French
http://www.chapitre.com
• Boeknet - De Nederlandse Internet Boekhandel (Dutch)
http://www.boeknet.nl/
112
Examples
Book databases accessible free of
charge: examples (Part 3)
• Proxis (Belgium)
http://www.proxis.be/
• Virtual Book Shop (good for old books)
http://www.bookshop.com/
113
114
Free public access bibliographic book
database + price comparisons
• Even comparisons of the catalogues of shops of books
(as well as of music, movies and many other goods)
are available free of charge.
• See for instance
»http://www.bookfinder.com/
»http://www.dealtime.com/
Examples
Example of an international
public access dissertation database
• The dissertation database of UMI is available from:
http://wwwlib.umi.com/dissertations/
A part is available free of charge.
115
116
Examples
Database of links to the
full text of many books
• A database (accessible free of charge )
of links to the full text of many books:
http://digital.library.upenn.edu/books/
117
Examples
Collection of links to
public access book databases
• See for instance Internet directories like Yahoo! that lead
to information about books.
118
Current awareness service
for books
• Some systems can alert the user that a new book has been
published when this fits the interest profile of the user.
• Such an interest profile can be stored on the server of the
system in the form of
»keywords, or
»subject categories / subject fields
• Example: http://www.amazon.com
119
Online access information
sources and services
Library
Online Public Access Catalogues
= OPACs
120
Online Public Access Catalogues of
libraries
• Mainly to find older books, the catalogues of libraries can
be useful.
• Most are accessible online and free of charge.
121
Online Public Access Catalogues
= OPACs: definition
Online Public Access Catalogue:
a term used to describe any type of computerized library
catalog offered to the public by online login
122
Example
Online access library catalogues:
The Library of Congress, U.S.A.
• >15 million books
+
>10 million other documents
• In Washington DC, U.S.A.
• Accessible online via WWW
• Access free of charge
123
Online access information
sources and services
Fee-based online public access
information services
124
Types of online access information
systems: “free” versus “fee”
• A lot of the information on the Internet is available free of
charge, but another part is only accessible when a fee is
paid to the producer and / or the distributor.
• Some organisations pay these fees for some sources and
then organise access, so that the members of the
organisation can retrieve and exploit the information as if
it is free of charge.
• The first commercial computer systems that make
information available online were born around 1975.
• Most of them are now also available through the Internet.
125
Examples
Fee-based online access services:
examples (Part 1)
Name
Location of the computer(s)
America On Line
OCLC
Ovid Technologies
CompuServe
Cambridge
Data-Star
Dialog
EBSCO
U.S.A.
U.S.A.
U.S.A.
U.S.A.
U.S.A., Taiwan, UK
Switzerland
U.S.A.
U.S.A.
126
Examples
Fee-based online access services:
examples (Part 2)
Name
Location of the computer(s)
Elsevier ScienceDirect
Factiva
ISI (Web of Science, JCR,…)
LexisNexis
MSN (Microsoft)
Prodigy
Silver Platter
STN
Swets (e-journals)
...
U.S.A.
U.S.A.
U.S.A.
U.S.A., The Netherlands,...
Germany - U.S.A. - Japan
The Netherlands
...
127
Online information services:
various names for similar systems
• (fee-based) online (access) information service
• (fee-based) online (access) computer service
• databank
• database vendor
• host computer
• aggregator
• ...
128
Online information services:
total size of their databases
In 1999:
The big host systems and the public access WWW pages
offer a comparable quantity of information:
• WWW offered about 8 terabytes (= 8 000 gigabytes) of
text data
(according to Lawrence and Lee Giles, Nature, 1999, Vol. 400, pp. 107-109.)
• Dialog offered about 9 terabytes (= 9 000 gigabytes)
(in 1998)
»6 billion pages of text
»3 million images
129
Databases of
online public access databases
• Example
»Gale directory of databases !
• Their coverage:
»online access databases
»(databases accessible on CD-ROM)
»...
130
Databases of databases:
Gale
• Produced in U.S.A.
• Not free of charge
• Available in various formats:
»printed
»on CD-ROM
»online via the host systems Data-Star, Dialog,
with a payment required for each use
»online through the Internet through various hosts,
for a fixed price per year to be paid in advance
131
Online access information
sources and services
Online access databases about journal articles
132
Online access databases
about journal articles: overview
• Thousands of fee-based online access databases offer
bibliographies or full-texts of journal articles in
particular subject domains.
• Only few large databases offer access to bibliographies of
articles published in journals, free of charge.
Example
Online access databases
about journal articles: Northern Light
• Northern Light allows searching for the full text of articles
from many journals/magazines.
• Searching is free of charge.
• Available from
»http://www.northernlight.com/
»http://www.nlsearch.com/
• Payment is required to receive the full text of an article.
133
Example
Online access databases
about journal articles: Ingenta (1)
• Ingenta Journals allows you to search a bibliographic
database of millions of journal articles,
including titles, authors, in many cases abstracts.
• Searching is free of charge.
134
Example
Online access databases
about journal articles: Ingenta (2)
• Payment is required to receive the full text of an article.
• Ingenta has acquired Uncover in 2000.
• Available from
»http://www.ingenta.co.uk/
»http://www.ingenta.com/
135
Example
Online access databases
about journal articles: Article@INIST
• Article@INIST allows you to search in a bibliographic
database, NOT full-text
(Journal articles, Journal issues, Books, Reports or
Conferences, doctoral dissertations)
at the Institut de l'Information Scientifique et Technique,
France.
• Searching is free of charge.
• Available from
http://form.inist.fr/public/eng/conslt.htm
• Payment is required to receive the full text of an article.
136
137
Example
Online access databases
about journal articles: Infotrieve
• Infotrieve allows you to search free of charge in a
bibliographic database of the articles of more than 20 000
journal titles and conference proceedings, NOT full-text.
• Current awareness services are also offered free of
charge.
• Available from http://www3.infotrieve.com/
• Payment is required to receive the full text of a document.
Example
Online access databases about journal
articles: Medline
• Medline produced by the
National Library of Medicine (USA)
allows searching a bibliographic database of articles in
the field of medicine.
• free of charge
• available from many sites, including
»PubMed of the National Library of Medicine (USA)
and
»Ingenta
138
Example
Online access databases about journal
articles: Medline through PubMed
139
140
Online access databases
about journal articles: Web of Science
• The Web of Science offers access through the WWW to a
database of bibliographic descriptions of scientific journal
articles in all subject domains.
• This database is (only) available to members of
organisations/institutes/companies/consortia that pay a
yearly fee to the producer/publisher of the database.
• This database is not only suitable for subject searching,
but also for citation searching.
141
Online access information
sources and services
Electronic newsletters and journals
142
Electronic newsletters and journals:
introduction
• Since the end of the 1990s, electronic journals have
become a new communication medium that cannot be
neglected.
Author / Sender
Editor
Reader / Receiver
143
Electronic newsletters and journals:
variations on a theme
• We can distinguish several methods
»of distribution and access
»of formatting the information (PDF, HTML,…)
»of pricing and licensing
»of restricting access
(authentication and authorization of legitimate users)
»to integrate access to e-journals with access to other
information sources
144
Electronic newsletters and journals:
various types and the price of access
• We can distinguish various types:
»equivalents of a version printed on paper
—Published almost simultaneously
—Print version published long time before electronic
version = long delay for the electronic version
»purely electronic publications
• Price of access: from free of charge to very expensive
145
Electronic newsletters and journals:
access and distribution methods
Many different methods are
used:
»anonymous ftp
»gopher
»WAIS
»electronic mail, listserv,...
»Usenet News
»loaded on local systems
in universities or
institutes
»http, WWW !
146
Electronic newsletters and journals
through the WWW
• The WWW has become the most important platform for
access to electronic newsletters and journals.
Example
Electronic newsletters and journals:
example
147
Example
Electronic newsletters and journals:
example
148
149
Specialised directories of online access
electronic journals
• Several directories / catalogs / overviews / databases / lists
are available of electronic, computer-based, online
accessible newsletters, newspapers, journals,... in
particular subject domains.
• For example: a directory of journals in medicine
accessible free of charge:
http://www.freemedicaljournals.com/
150
Online access information
sources and services
Computer-based information sources:
criteria to evaluate their quality
151
Computer-based information sources:
evaluation criteria (Part 1)
Besides more general criteria applicable to all information
sources, for those sources that are based on computers
and networks we see the following criteria:
• Easy to navigate?
»User-friendly information system?
»Easy for users to orientate themselves within the resource
and to find their way around it?
»Is the resource organised into manageable chunks of
information that can be browsed easily?
152
Computer-based information sources:
evaluation criteria (Part 2)
»
Is a contents page or index offered that describes what
is contained within the site?
»
Are there good navigational links within the pages (e.g.
'back', 'forward', 'home')
»
Are the links clearly labeled?
»
Is the navigation process supported by images?
»
Is there a single downloadable file for documents that
exist as a series of separate pages?
»
Is there a search facility within the resource?
153
Computer-based information sources:
evaluation criteria (Part 3)
• Good user support?
»Good support that is offered to users to help them answer
queries and problems that arise whilst using the resource?
»Good computer-based, contextual help, documentation,
training materials or tutorials?
»E-mail contact(s) and telephone number(s) available?
154
Computer-based information sources:
evaluation criteria (Part 4)
• Based on appropriate technologies?
»Are technologies and standards used that will enable users
to access and utilize all aspects of the resource?
»Does the resource avoid that proprietary software should
be used?
»Does the resource avoid the use of proprietary extensions
to HTML, which some browsers will not be able to
recognize?
155
Computer-based information sources:
evaluation criteria (Part 5)
»Does the format allow access to the resource for all users,
even for instance sight impaired and those who can only
navigate by using the keyboard?
• Information integrity / High stability of the contents /
Low volatility of the contents?
»Is there adequate maintenance of the information content?
156
Computer-based information sources:
evaluation criteria (Part 6)
• System integrity?
»Site integrity relates to the stability of the site over time.
This usually relates to the work of the site manager or web
master.
»Realise that individual sites can be moved or withdrawn at
any time by those responsible for publishing information
on the Internet, and that addresses, file structures, formats
and interfaces can be altered without warning.
»Is the site current and up to date?
157
Computer-based information sources:
evaluation criteria (Part 7)
» Is the site proven to be or expected to be durable in nature?
» Is the site adequately administered and maintained?
158
Computer-based information sources:
The Internet Detective
A tutorial in English about how to assess the quality of
WWW-based information resources can be accessed
online free of charge through the WWW:
http://www.netskills.ac.uk/TonicNG/cgi/sesame?detective
159
Online access information
sources and services
Future trends
160
Online access information:
future trends
• An increasing amount of information becomes available
online.
• A growing amount of this online information becomes
available free of charge.
• The quality of server and client software is growing.
A consequence is:
• An increasing number of end-users searching for
information online.
161
Online access information:
conclusion
• In the case of simple information needs, the WWW and the
search tools can work like “magic”.
• However, in the case of more complicated information
needs, there is still is no “magic button” that brings you
immediately to all the required information.
Thank you
The slides are available through the WWW from
http://www.vub.ac.be/BIBLIO/nieuwenhuysen/presentations/
Any questions?
162